Relationship between climate, pollen concentrations of Ambrosia and medical consultations for allergic rhinitis in Montreal 1994-2002

The aim of this study is to evaluate the influence of meteorological factors on Ambrosia pollen concentrations and its impact on medical consultations for allergic rhinitis of residents from various socio-economic levels in Montréal (Québec, Canada) between 1994 and 2002. The study was conducted to recognize the sensitivity of pollen productivity to daily climate variability in order to estimate the consequences on human health vulnerability in the context of global climate change. Information related to medical consultations for allergic rhinitis due to pollen comes from the Quebec Health Insurance Board (Régie de l'assurance-maladie du Québec). Ambrosia pollen concentration was measured by the Aerobiology Research Laboratories (Nepean, Ontario). Daily temperature (maximum, minimum, and mean) and precipitation data were obtained from the Meteorological Service of Canada. Socio-economic data come from the 1996 and 2001 census data of Statistics Canada. Between 1994 and 2002, during the Ambrosia pollen season, 7667 consultations for allergic rhinitis due to pollen were recorded. We found a significant association between the number of medical consultations and pollen levels. Significant associations were detected for over-consultation the day of exposure, 1, 2, 3 and 5 days after exposure to high levels of pollen. The consultation rate is higher from low-income residents (3.10 consultations per 10,000 inhabitants) than for high-income (1.65 consultations per 10,000 inhabitants). Considering the demonstrated impact of pollen levels on health, it has become critical to ensure adequate monitoring of Ambrosia and its meteorological sensivity in the context of the anticipated climate change and its potential consequences on human health.